54 



BULLETIN GO, TtNTTED STATES NATIONAL MUSEUM. 



SCALPELLUM ALBATROSSIANUM, new species. 



Ti/pe.— Cat No. 32891, U.S.N.M. 



Type-localit\j. — Alhatrom Station 2226, off Cape Hatteras, north 

 latitude 37°, west longitude 71° 54', in 2,045 fathoms, on Scalpelluin 

 reglum. 



The capitulum is fully twice as long as wide, widest in the middle, 

 tapering toward })ase and summit. The occludent margin is regularly- 

 arched, summit a trifle recurved. Composed of thirteen fully calcified 

 plates, separated by very narrow chitinous sutures. The plates are 

 distinctly marked with lines of growth, and covered with a thin, 

 shortly and rather sparsely pilose cuticle. 



The scutum is slightly more than twice as long as wide, its occlud- 

 ent margin regularly arcuate. The lateral margin is a])out two-thirds 

 as U)ng as the scutal. It is deeply sinuated, for the reception of the 



apex of the upper latus, just below the tergo- 

 lateral angle, which is extended in a narrow 

 acute lobe. The baso-lateral angle is rounded, 

 and rests for a short distance against the in- 

 framedian latus. 



The tergum is triangular, longer, and wider 

 than the scutum. Occludent margin arcuate, 

 basal margin straight, carinal margin weakly 

 sigmoid, being concave above, convex below. 

 The apex of the carina reaches its upper third. 

 The apex is a trifle recurved. 



The carina is strongly arched above, less 

 so in the lower half. The umbo is apical, 

 against but not between the terga. The roof 

 is flat, bounded by very low, narrow ribs. 

 The sides are wide in the upper half, narrow 

 and tapering in the lower. 



The upper latus is triangular in general outline, but with five facets. 

 The scutal margin is longest, slightly concave; the tergal is a little 

 shorter, a trifle convex. The carinal margin is about half as long as 

 the scutal and a little shorter than the carino-lateral. The very short 

 basal margin is in contact with the summit of the inframedian latus. 

 The umbo is terminal, projecting into a recess in the scutum. 

 There is no rostrum. 



The rostral latus is wider than high, with the umbo slightly pro- 

 jecting from the rostral margin. The straight basal margin curves 

 into the lateral margin. 



The inframedian latus is oblong, about three times as high as wide, 

 with slightly raised central mucro, from which low ribs radiate to the 

 angles of the plate. The upper end is truncated, and the base is a little 

 dilated laterally. 



Fin. li).— ScALPELLUM ALBATROSSI- 

 ANUM X 4. 



